A single technology may not be equally effective in transmitting information through both space and time. Our thinking for the past half millennium has been the product of a world where the dominant information technology accomplished both objectives fairly well. As we enter the electronic era, we must try to think again of transmission through space and time as separate issues. Assumptions derived from a print-based environment about permanence and the cumulative growth of knowledge may give to a heightened awareness of the fragility and vulnerability of the stock of human knowledge, and a return to the unending medieval preoccupation with preservation and recovery.